I have used "Elmers Washable School Glue Sticks, goes on purple, dries clear" for years. I do lots of applique work. I've never had problems with the purple staining the fabric. I buy a bunch at the beginning of the school year because WalMart and such places usually sell them cheaply then for back-to-school sales.

When I rinse out the glue, I always use a large vat of water like the bath tub or washing machine for big projects, but just the kitchen sink for a single block.

You can usually get these for about a dollar a stick. I get the multi packs. I prefer the smaller sticks and use more of them, than the larger sticks which may dry out once opened if you don't use them up right away.